1, according to Ch.8, what is the purpose of Sirius 4?
The purpose is to find the pathfinder and enable Mark to communicate with earth.
2, The higher-ups decide not to tell the Ares 3 crew that Mark is still alive. But the general public at this point is already aware that he is. Where are the crew members now and how is it possible that they have no access to such information as regard to Mark's current status?
The other crew members were still on Hermes then, they wouldn’t find out what’s really going on on earth or Mark. And the authority thought they should stick to their missions and not be effected by their remorse.
3, Mark is now on his path to find the Pathfinder, and of course, he finds it. (Duh!) So, the questions for today are: why is navigation tricky? And how does he overcome this issue?
The way of finding pathfinder is smooth but lack of landmarks. Map or compass is not solution to this problem either. By using a satellite as a guide, he successfully find his way back to his Mars home.
4, Communication is now set up. But there's a slight problem. At first, all communications are done through a camera, but why can’t Mark use the alphabet to "receive" messages but have to resort to a seemingly more complex system?
The angle issue. 26 letters plus his card can’t be accurately seen at this small angle (13 degrees?). Then he used ASCIII on this issue.
Sorry I only finished this book on Chapter11.